RADIATION BY CHARGED-PARTICLES IN NONUNIFORM ACCELERATION - THE INAPPLICABILITY OF LARMORS FORMULA

A recent work which explained synchrotron radiation as an inverse Comp ton effect [R. Lieu and W. I. Axford, Astrophys. J. 416, 700 (1993)] h ighlighted the importance of coherence in characterizing the radiation from a relativistic electron. In this paper we demonstrate explicitly that the well-known Larmor formula for the classical radiative loss r ate of a circulating charge is only valid in the limit of constant acc eleration. When the acceleration varies significantly over a ''radiati on formation length,'' the radiation properties are determined by cohe rent interference in an orbit-dependent way, and spectra and total los s rates are modified nontrivially. Vile illustrate these effects by co nsidering a representative trajectory where analytical results are ava ilable.